Decellularized omentum matrix and uses thereof

Abstract

Methods for defatting omentum and processes for preparing an acellular omentum, i.e., devitalized or decellularized omentum, comprising extracellular matrix for implantation into a mammalian system. Constructs for medical applications comprising decellularized omentum are also described. More specifically, mesh reinforced omentum biomatrix for soft tissue repair is described.

We claim: 
     
       1. A method of delipidizing an omentum, the method comprising:
 (i) freeze-drying an omentum; 
 (ii) heating the freeze-dried omentum to a temperature in the range of about 37° C. to about 40° C.; 
 (iii) compressing the heated omentum to express fats and other lipids, thereby yielding a partially-delipidized omentum, wherein the step of compressing the heated omentum comprises gradually increasing the force of compression to at least about 22,000 lbs.; and 
 (iv) contacting the partially-delipidized omentum with an extraction solvent to extract therefrom at least some of the remaining fats and other lipids, wherein (A) the extraction solvent is selected from the group consisting of hexane, cyclohexane, xylene, benzene, toluene, ethyl acetate, acetone, dioxane, acetonitrile, and combinations thereof, or (B) the extraction solvent is supercritical carbon dioxide. 
 
     
     
       2. The method of  claim 1 , further comprising, before step (i), mechanically processing the omentum into a plurality of pieces having a longest dimension in the range of about 1 mm to about 5 mm. 
     
     
       3. The method of  claim 1 , further comprising, before step (ii), mechanically processing the freeze-dried omentum into a plurality of pieces having a longest dimension in the range of about 1 mm to about 5 mm. 
     
     
       4. The method of  claim 1 , wherein the extraction solvent is selected from the group consisting of hexane, cyclohexane, xylene, benzene, toluene, ethyl acetate, acetone, dioxane, acetonitrile, and combinations thereof. 
     
     
       5. The method of  claim 1 , wherein the extraction solvent is supercritical carbon dioxide. 
     
     
       6. The method of  claim 1 , wherein step (iv) comprises:
 (1) contacting the partially-delipidized omentum with a polar solvent selected from the group consisting of acetone, dioxane, acetonitrile, and combinations thereof; 
 (2) thereafter, contacting the partially-delipidized omentum with a first solvent mixture comprising both the polar solvent and a non-polar solvent selected from the group consisting of hexane, cyclohexane, xylene, benzene, toluene, ethyl acetate, and combinations thereof, wherein (A) the concentration of the polar solvent is about 30% to about 50% by weight of the first solvent mixture and (B) the concentration of the non-polar solvent is about 50% to about 70% by weight of the first solvent mixture; and 
 (3) thereafter, contacting the partially-delipidized omentum with a second solvent mixture comprising both the polar solvent and the non-polar solvent, wherein (A) the concentration of the polar solvent is about 10% to about 30% by weight of the second solvent mixture and (B) the concentration of the non-polar solvent is about 70% to about 90% by weight of the second solvent mixture. 
 
     
     
       7. The method of  claim 6 , wherein the polar solvent is acetone and the non-polar solvent is cyclohexane. 
     
     
       8. The method of  claim 7 , wherein the weight ratio of the partially-delipidized omentum to the polar solvent in step (iv)(1) is about 1:3 to about 1:50, the weight ratio of the partially-delipidized omentum to the first solvent mixture in step (iv)(2) is about 1:3 to about 1:50, and the weight ratio of the partially-delipidized omentum to the second solvent mixture in step (iv)(3) is about 1:3 to about 1:50. 
     
     
       9. The method of  claim 1 , further comprising, as step (v), rehydrating the delipidized omentum. 
     
     
       10. The method of  claim 9 , further comprising, as step (vi), decellularizing the rehydrated delipidized omentum. 
     
     
       11. The method of  claim 10 , further comprising, as step (vii), disinfecting the decellularized omentum. 
     
     
       12. The method of  claim 11 , wherein step (vii) further comprises sterilizing the decellularized omentum. 
     
     
       13. A construct for medical purposes comprising an omentum processed in accordance with the method of  claim 12 . 
     
     
       14. A method of making a foam decellularized delipidized omentum, the method comprising:
 providing an omentum processed in accordance with the method of  claim 12 ; 
 preparing a suspension of the omentum in 0.1N HCl; 
 homogenizing the suspension into an omentum slurry; 
 pouring the omentum slurry into a mold; 
 placing the mold containing the omentum slurry into a lyophilizer; and 
 lyophilizing the omentum slurry, yielding the foam decellularized delipidized omentum. 
 
     
     
       15. The method of  claim 14 , further comprising crosslinking the foam decellularized delipidized omentum. 
     
     
       16. The method of  claim 14 , further comprising placing a woven or nonwoven mesh in the mold prior to or partway through pouring the omentum slurry into the mold. 
     
     
       17. A foam decellularized delipidized omentum prepared in accordance with the method of  claim 14  or  claim 15 . 
     
     
       18. A mesh-reinforced omentum prepared in accordance with the method of  claim 16 . 
     
     
       19. A method of treatment of myocardial infarction comprising:
 providing a foam decellularized delipidized omentum prepared in accordance with the method of  claim 14  or  claim 15 ; 
 seeding the foam decellularized delipidized omentum with adipose-derived stem cells; 
 accessing a heart having an infarct area; and 
 applying the adipose-derived stem cell seeded foam decellularized delipidized omentum to the infarct area.